Spark-producing device.



F. A. THURSTON. SPARK PRODUCING DEVICE.

APPLIGATION FILED 00T. 17, 1904.

Patented Feb. 22, 1910,

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SPARK-PRODUCING DEVICE.

Specification of Letters Patent.

Patented Feb. 22, 1910.

Application led Gctober 17? 1904. Serial No. 228,816,

To all whom it may concern:

Be it knownthat l, FREDUs A. THURs'roN, a citizen of the United States,residing at Chicago, in the county of Cook and State ot' Illinois, haveinvented a certain new and useful Improvement in Spark- ProducingDevices, of which the following is arfull, clear, concise, and exactdescription, reference being had to the accompanying drawings, forming apart of this specification.

My invention relates to spark plugs for explosive engines for use inmotor vehicles', launches and the like.

Prominent objects of the invention are to provide a simple, practicaland inexpensive form of spark plug; to secure reliability andeffectiveness of action; to prevent injury of any kind to the operatingparts of the device either by heat, gas or water or otherwise; to securea larOe and bright flash; to procure' very high eiciency of action, andto secure the foregoing and other desirable results in a simple,practical and effective manner.

In the accompanying drawings, Figure 1 is a longitudinal sectlon of aspark plug embodying my invention. Figs. 2 and 3 are respectively a topand bottom plan view of the device, and Fig. 4 is a cross section takenon line 4, 4, in Fig. 1.

The spark plug shown in the drawings for carrying out my inventioncomprises a shell or casing 1 conveniently of cylindrical form and madeclosed at one end and open at its other end. The open end is preferablythreaded as at 2 to permit the device to be readily screwed into and outof the cylinder of the engine or other device in which the plug is to beused. Within the shell or casing 1, which is desirably formed of metalsuch as brass, is a spool or bobbin 3 on which is wound a coil of linewire 4. The bobbin 3 is desirably made of metal, as for example, ofiron, and consists ofa central spindle 5 and a pair of end flanges 6, 6,which are but very little smaller than the interior of the shell orcasing 1. The layer 7 of insulating material, preferably fire-proofalso, as for example asbestos, is arranged immediately outside of thespindle 5 of the bobbin, and layers 8, 8, of the same or similarmaterial are arranged inside of the flanges 6, 6, of the bobbin. A layer9 of the same or similar material is arranged between the coil of wireand the shell 1, and layers 10 and 11 at the upper and lower ends ofsaid bobbin. Thus the entire bobbin with this coil of wire is inclosedin asbestos or similar material, thereby insulating it both electricallyand thermally from the shell l and at the same time the coil of wire 4is similarly insulated from the bobbin.

A metallic cap 12 is fitted into the shell 1 and outside of the asbestosat the lower end of the spool, thereby forming a metallic covering orprotection for the asbestos at the open end of the plug. The spool with.this asbestos covering fits tightly within the interior of the shell orcasing 1 and the cap 12 tits tightly at the lower end of the spool,whereby the parts are held in position and a tight and compact structureis formed, and atthe same time the coil of wire is thoroughly protectedfrom gases, water and heat in the cylinder to which the plug may beattached. A pin 14 is secured to the lower 4flange 6 of the bobbin 3,being desirably made integral therewith. The cap 12 is provided withinsulation 15 surrounding the pin 14. An armature 16 is pivotallyconnected with the lower portion of the shell and arranged to extendacross the lower end of the bobbin 3, whereby the latter when magnetizedor energized by the coil 4 will attract the armature. The pin 14 has itsend bent, and the armature 16 has a contact 17 adapted to makeconnection with the bent end of the pin 14, whereby a make and breakaction can take place as a result of the energization and denergizationof the metallic bobbin forming as it were the core of an electromagnet.This make and break action produces a spark which is-efective inigniting the gas or other material to be exploded in the enginecylinder. The pivotal connection for the armature 16 is convenientlypro- A vided by driving astaple 18 into the lower end of the shell 1.The upper closed end of the shell is provided with an aperture which islled with insulating material 20 such as lava, cement or the like, andin this is embedded a threaded pin or spindle 21 provided with nuts 22and 23. One end 24 of the wire forming the coil 4 is connected with thepin 21, and the other end of said coil is connected with the metalbobbin 3. One side of the battery is connected with the pin 21 by thenuts 22 and 23, and the other is connected with the engine cylinder orsome other part of the engine. Thus the circuit is made from the pin 21to the coil 4, thence by the bobbin 3 to the pin 14 and thence by thearmature 16 to the shell 1 and engine cylinder to battery. When thearmature 16 is attracted by the energization of the coil 4 the armature16 is separated from the pin 14, thereby opening the circuit andallowing said armature to fallback against the pin 14 to thereby closethe circuit again. Thus a continual vibratory action of the armature isset up with the result of formation of sparks due to they selfVinduction at make and break. y

The device is very simple and practical, and in addition .to the abovementioned advantages of being thoroughly protected from heat, gases andWater and being Well insulated electrically, it is very etlicientrequiring but a small percentage of the usual amount of battery employedin devices of this kind.

It Will be understood that changes and modifications can be made Withoutdeparting from the invention.

What I claim is l. A spark plug, comprising a tubular metal casing,having oneof its ends closed and its other end open, a coil confinedWithin said casing and surrounded by an insulating sheath, a core forsaid coil, an armature confined Within the open end `of the metal casingbut separated from the core and the coil by insulation and also by ametal Wall, a terminal at the closed end of the casing, and insulatingmaterial in which said material is embedded, said insulating materialbeing extended through the closed end of said casing. f

2. A spark plug comprising a metallic shell or casing having an open endand adapted for insertion into and bodily removable from an enginecylinder, a spark coil confined Within said casing, insulating materialsurrounding said spark coil, said Coil having a metallic bottom adaptedto act as a magnet, an armature pivoted at the end of said plug Which isto be inserted in the cylinder, a contact carried by said armature, saidarmature and Contact being in the openv end of said shell or casing, anda metallic connection extending through and insulated from the other endof said casing and connected With said spark coil.

In Witness whereof, I hereunto vsubscribe my name this 7 th day ofOctober A. D., 1904.

FREDUS A. THURSTON.

Witnesses A. MILLER BELFIELD, E. BERG.

